Jfe Steel Corporation

Ginza Maronie P.c.

Ryuichi Suehiro

Toshito Takamiya

Takeshi Imamura

Makoto Watanabe

Takashi Terashima

Masanori Uesaka

Yukihiro Shingaki

Hiroi Yamaguchi

Seiji Okabe

Shigehiro Takajo

Hirotaka Inoue

Kazutoshi Hanada

Naoki Watanabe

Yasuyuki Hayakawa

Takayuki Fukunaga

Souichiro Yoshizaki

Yuiko Wakisaka

Yuu Nagai

Ryosuke Watanabe

Ryota Hosoya

Provided are methods that can prevent either or both of kinking and collapsing of a steel sheet coiled in coil form regardless of the characteristics of the steel sheet. A method of determining a tension pattern of tension applied to a steel sheet to coil the steel sheet in coil form comprises calculating the tension pattern using an apparent elastic modulus in a radial direction of a coil.

Method of determining tension pattern and method of coiling steel sheet

A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): MM(XO). . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900&#xb0; C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0&#xb0; C.

Grain-oriented magnetic steel sheets having chromium-free insulating tension coating, and methods for producing such steel sheets

A grain-oriented electrical steel sheet having excellent iron loss property is produced from a steel slab containing, by mass %, C: 0.002-0.15%, Si: 2.5-6.0%, Mn: 0.01-0.80%, Al: 0.010-0.050% and N: 0.003-0.020%, when: a heating rate between 500-700&#xb0; C. in decarburization annealing is not less than 80&#xb0; C./s, a surface roughness Ra of a work roll in final cold rolling is 0.01-3.0 &#x3bc;m, a total content of alkaline earth metals to MgO in annealing separator is 0-5 mass %, an average length L in rolling direction of passed crystal grains is not more than 25 mm, a ratio of crystal grains having a length in rolling direction of not more than 5 mm is 40-90%, and an existence ratio of alkaline earth metal sulfides having a size corresponding to circle of not less than 0.5 &#x3bc;m in a cross section of forsterite film is not more than 0.2/&#x3bc;m per unit length in sheet width direction.

Grain-oriented electrical steel sheet and method for producing the same

Provided are an insulation-coated oriented magnetic steel sheet having an insulating coat with excellent heat resistance; and a method for manufacturing the same. This insulation-coated oriented magnetic steel sheet has an oriented magnetic steel sheet, and an insulating coat arranged on the surface of the oriented magnetic steel sheet, the insulating coat containing Si, P, O, and Cr, and at least one element selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn. The XPS spectrum of the outermost surface of the insulating coat has peaks observed at Cr2pand Cr2p.

Insulation-coated oriented magnetic steel sheet and method for manufacturing same

Provided are an insulating-coated oriented magnetic steel sheet having an insulating coating of excellent heat resistance, and a method for manufacturing the same. This insulating-coated oriented magnetic steel sheet has an oriented magnetic steel sheet, and an insulating coating arranged on the surface of the oriented magnetic steel sheet. The insulating coating contains Si, P, and O, and at least one element selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn, the K-absorption edge of the P in the insulating coating having an XAFS spectrum that exhibits three absorption peaks from 2156 eV to 2180 eV.

Insulating-coated oriented magnetic steel sheet and method for manufacturing same

When a steel sheet containing Si: 2-5 mass % after cold rolling is subjected to a primary recrystallization annealing and a finishing annealing for secondary recrystallization to form a grain-oriented electrical steel sheet, the primary recrystallization annealing is performed by rapid heating in the heating process and temperature keeping treatment at a certain temperature in the course of the heating to thereby obtain a grain-oriented electrical steel sheet having plural peaks in a distribution of misorientation angle between crystal orientation of secondary recrystallized grains and Goss orientation, wherein misorientation angle of the second smallest peak among the plural peaks is preferably not less than 5&#xb0; and a grain size of secondary recrystallized grains is not more than 15 mm.

Grain-oriented electrical steel sheet

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO; and HPO, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy:0.20&#x2264;([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]&#x2264;0.45&#x2003;&#x2003;(1).

Treatment solution for chromium-free tension coating, method for forming chromium-free tension coating, and grain oriented electrical steel sheet with chromium-free tension coating

There is provided a grain-oriented electrical steel sheet stably having excellent magnetic characteristics and coating adhesion even when a rapid heating is conducted in a primary recrystallization annealing (decarburization annealing). Concretely, it is a grain-oriented electrical steel sheet provided on its sheet surface with a tension-applying type insulation coating constituted with a coating layer A formed on a steel sheet side and mainly composed of an oxide and a coating layer B formed on a surface side and mainly composed of glass, characterized in that a ratio R (&#x3c3;/&#x3c3;) of a tension &#x3c3;of the coating layer B on the surface side applied to the steel sheet to a tension &#x3c3;of the coating layer on the steel sheet side A applied to the steel sheet is within a range of 1.20-4.0.

Grain-oriented electrical steel sheet having excellent magnetic characteristics and coating adhesion

A method for producing a grain-oriented electrical steel sheet by subjecting a slab of an inhibitor-less ingredient system containing C: 0.002-0.10 mass %, Si: 2.5-6.0 mass %, Mn: 0.010-0.8 mass % and extremely decreased Al, N, Se and S to hot rolling, hot band annealing, cold rolling, decarburization annealing, application of an annealing separator and finish annealing, when a certain temperature within range of 700-800&#xb0; C. in a heating process of decarburization annealing is T1 and a certain temperature as a soaking temperature within a range of 820-900&#xb0; C. is T2, a heating rate R1 between 500&#xb0; C. and T1 is set to not less than 100&#xb0; C./s and heating rate R2 between T1 and T2 is set to not more than 15&#xb0; C./s, whereby grain-oriented electrical steel sheet having excellent iron loss property and coating peeling resistance is obtained in the inhibitor-less ingredient system while ensuring decarburization property even when rapid heating is performed during decarburization annealing.

Method for producing grain-oriented electrical steel sheet

In a method for producing a grain-oriented electrical steel sheet by subjecting a slab containing C: 0.002-0.10 mass %, Si: 2.5-6.0 mass %, Mn: 0.01-0.8 mass % and further containing Al and N, or S and/or Se, or Al, N, S and/or Se as inhibitor ingredients to hot rolling, hot band annealing, cold rolling, decarburization annealing, application of an annealing separator and finish annealing, when a certain temperature within a range of 700-800&#xb0; C. in a heating process of the decarburization annealing is T1 and a certain temperature as a soaking temperature within a range of 820-900&#xb0; C. is T2, a heating rate R1 between 500&#xb0; C. and T1 is set to not less than 80&#xb0; C./s and a heating rate R2 between T1 and T2 is set to not more than 15&#xb0; C./s, whereby a grain-oriented electrical steel sheet having excellent magnetic properties and peeling resistance of forsterite coating is obtained while ensuring decarburization property.

In a method for producing a grain-oriented electrical steel sheet by comprising a series of steps of hot rolling a raw steel material comprising C: 0.002-0.10 mass %, Si: 2.0-8.0 mass %, and Mn: 0.005-1.0 mass %, subjecting the steel sheet to a hot band annealing as required, cold rolling to obtain a cold rolled sheet having a final sheet thickness, subjecting the steel sheet to primary recrystallization annealing combined with decarburization annealing, applying an annealing separator to the steel sheet surface and then subjecting to final annealing, rapid heating is performed at a rate of not less than 50&#xb0; C./s in a region of 200-700&#xb0; C. in the heating process of the primary recrystallization annealing, and the steel sheet is held at any temperature of 250-600&#xb0; C. in the above region for 1-10 seconds, while a soaking process of the primary recrystallization annealing is controlled to a temperature range of 750-900&#xb0; C., a time of 90-180 seconds and P/Pin an atmosphere of 0.25-0.40, whereby a grain-oriented electrical steel sheet being low in the iron loss and small in the deviation of the iron loss value is obtained.

In a method for producing a grain-oriented electrical steel sheet by hot rolling a raw steel material containing C: 0.002&#x2dc;0.10 mass %, Si: 2.0&#x2dc;8.0 mass % and Mn: 0.005&#x2dc;1.0 mass % to obtain a hot rolled sheet, subjecting the hot rolled sheet to a hot band annealing as required and further to one cold rolling or two or more cold rollings including an intermediate annealing therebetween to obtain a cold rolled sheet having a final sheet thickness, subjecting the cold rolled sheet to a primary recrystallization annealing combined with decarburization annealing, applying an annealing separator to the steel sheet surface and then subjecting to a final annealing, when rapid heating is performed at a rate of not less than 50&#xb0; C./s in a range of 100&#x2dc;700&#xb0; C. in the heating process of the primary recrystallization annealing, the steel sheet is subjected to a holding treatment at any temperature of 250&#x2dc;600&#xb0; C. for 0.5&#x2dc;10 seconds 2 to 6 times to thereby obtain a grain-oriented electrical steel sheet being low in the iron loss and small in the deviation of the iron loss value.

A grain-oriented electrical steel sheet allows for manufacture of a transformer that exhibits, when the steel sheet is applied to an iron core thereof, extremely low iron loss and extremely low noise properties, makes highly efficient use of energy, and can be used in various environments. The grain-oriented electrical steel sheet has a strain distribution in regions where closure domains are formed, when observed in a cross section in the rolling direction, with a maximum tensile strain in a sheet thickness direction being 0.45% or less, and with a maximum tensile strain t (%) and a maximum compressive strain c (%) in the rolling direction satisfying Expression (1):+0.06&#x2264;&#x2264;0.35&#x2003;&#x2003;(1).

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Tokyo, Japan

Ryuichi Suehiro